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Remediation Optimization uses defined approaches to improve the effectiveness and efficiency of an environmental remedy. Optimization approaches include site-wide optimization reviews, statistical evaluation tools, consideration of emerging technologies, review of operating system costs and the identification of cost reduction methods without loss of protectiveness.

Our technology guides collect information about many types of remediation technologies used to clean up contaminated sites. Current initiatives related to site cleanup, websites maintained by EPA and other federal agencies and state organizations, and recent documents are also included on this page.

In Situ Chemical Reduction places a reductant or reductant-generating material in the subsurface to degrade toxic organic compounds to potentially nontoxic or less toxic compounds. It immobilizes metals by adsorption or precipitation and degrades non-metallic oxyanions.

Electrokinetics applies low-intensity direct current through the soil between ceramic electrodes that are divided into a cathode array and an anode array. This current mobilizes charged species, causing ions and water to move toward the electrodes, and removal of contaminants at the electrode may be accomplished by several methods.

In Situ Chemical Oxidation typically involves reduction/oxidation (redox) reactions that chemically convert hazardous compounds to nonhazardous or less toxic compounds that are more stable, less mobile or inert.

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Nanoscale Materials for Environmental Site Remediation have been developed and used to remediate contaminated soil and groundwater, such as sites contaminated by chlorinated solvents or oil spills. Nanoscale materials can be highly reactive in part because of the large surface area to volume ratio and the presence of a larger number of reactive sites.

In Situ Flushing floods a zone of contamination with an appropriate solution to remove the contaminant from the soil. Contaminants are mobilized by solubilization, formation of emulsions or a chemical reaction with the flushing solutions and brought to the surface for disposal, recirculation or on-site treatment and reinjection.

Permeable Reactive Barriers are subsurface emplacements of reactive materials through which a dissolved contaminant plume must move as it flows, typically under natural gradient. Treated water exits the other side of the permeable reactive barrier.

Thermal Treatment (ex situ) generally involves the destruction or removal of contaminants through exposure to high temperature in treatment cells, combustion chambers or other means. Contaminated media is contained during the remediation process.

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Bioreactor Landfills rapidly transform, degrade and stabilize organic waste through the addition of liquid and air enhance microbial processes.

Combined Remedies may be necessary to clean up a contaminated site. Combined remedies take advantage of two or more technologies to enhance the performance of each and achieve a synergistic effect. Treatment trains are typically planned series of actions that address the problem.

Natural Attenuation relies on natural processes to clean up or attenuate pollution in soil and groundwater. Natural attenuation occurs at most polluted sites. However, the right conditions must exist underground to clean sites properly.

Thermal Treatment (in situ) includes many different methods and combinations of techniques to apply heat to polluted soil, groundwater or both. The heat can destroy or volatilize organic chemicals, and the gases can be extracted through collection wells for capture and cleanup in a treatment unit.

Bioremediation uses microorganisms to degrade organic contaminants in soil, groundwater, sludge and solids. The microorganisms break down contaminants by using them as an energy source or cometabolizing them with an energy source.

EPA prepares the Superfund Remedy Report to provide information and analyses on remedies EPA selected to address contamination at Superfund National Priorities List and Superfund Alternative Approach sites. This report is the latest in a series, prepared since 1991, on Superfund remedy selection. The latest edition focuses on the analysis of Superfund remedial actions selected in fiscal years 2018, 2019, and 2020.

Evapotranspiration Covers utilize natural processes to manage water precipitating on municipal landfills, hazardous and industrial waste landfills to contain waste.

Solvent Extraction uses an organic solvent to separate organic and metal contaminants from soil. The solvent is mixed with contaminated soil in an extraction unit and then passed through a separator, where the contaminants and extractant are separated from the soil.

Horizontal remediation wells (HRWs) are installed below ground parallel to the ground surface or at a shallow angle using horizontal directional drilling. HRWs offer an alternative to the installation of conventional vertical wells or trenching, particularly where access to soil and groundwater contamination is impeded by surface or near-surface obstructions.

Groundwater Circulating Wells create a three-dimensional groundwater circulation pattern that can provide subsurface remediation inside a well, in the aquifer or both. Groundwater is drawn into a well through one screened section and is pumped through the well to a second screened section where it is reintroduced to the aquifer.

Solidification and Stabilization encapsulates waste within a solid material, coat the waste with low-permeability materials to restrict contaminant migration or both. Solidification can be accomplished by mechanical processes or by a chemical reaction between a waste and binding reagents, such as cement, kiln dust, or lime/fly ash.

Soil Washing separates contaminants sorbed onto fine soil particles from bulk soil in a water-based system. Soils and wash water are mixed in a tank or other treatment unit and usually separated using gravity settling.

The data that forms the basis of the analyses contained in SRR 17th Edition can be found at Superfund Data and Reports by downloading Contaminant of Concern Data for Decision Documents by Media and Remedy Component Data for Decision Documents by Media.

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Soil Vapor Extraction applies a vacuum to unsaturated zone soil to induce the controlled flow of air and remove volatile and some semivolatile organic contaminants from the soil.

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Activated Carbon (AC)-Based Technology involves emplacement of AC-based amendments for in situ remediation of soil and groundwater. AC-based amendments remove contaminants through adsorption by AC and degradation by reactive amendments.

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Multi-Phase Extraction uses a vacuum system, sometimes combined with a downhole pump, to remove various combinations of contaminated groundwater, separate-phase petroleum product and vapors from the subsurface. The system lowers the water table around the well, exposing more of the formation for vapor extraction.

Air Sparging involves the injection of air or oxygen through a contaminated aquifer to remove volatile and semivolatile organic contaminants by volatilization. The injected air helps to flush the contaminants into the unsaturated zone for treatment.

Fracturing for Environmental Site Remediation technologies enhance or create openings in bedrock or soil with low effective porosity, such as clay, to help soil and groundwater cleanup methods work better.

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The older generation TASER probes X26 and X2 have been shown to be capable of piercing the skull with their tips. With the introduction of the new TASER 7 and the far more powerful TASER 10, concerns have arisen as to whether these weapons might penetrate the skull more deeply and thus prove to be potentially lethal. For this reason, we tested the penetration capacity of these weapons on polyurethane-gelatine-buckskin head simulants at different firing distances. The striking speeds and striking angles were documented with a high-speed camera, and the piercing depths were recorded by computed tomography. None of the probes penetrated the skull, but their tips did; TASER 7 probe tips pierced up to 5.6 mm, whereas TASER 10 probe tips pierced up to 10.4 mm. The TASER 7 probes fared better with regard to penetration depth at shorter firing distances; on the other hand, the TASER 10 probes pierced more deeply at distances of 3 to 4 m, with their flight stability improving after the first 2 m. Our results imply that TASER 7 and TASER 10 probes are not to be expected to cause great harm or even death when striking the head.

Phytotechnologies are broadly defined as the use of vegetation to address contaminants in soil, sediment, surface water and groundwater. Cleanup objectives for phytotechnologies can be contaminant removal and destruction, control and containment or both.